1. Incorporation by Reference
Applicant hereby incorporates herein by reference any and all U.S. patents and U.S. patent applications cited or referred to in this application.
2. Field of the Invention
This invention relates generally to fluid level monitoring devices, and more particularly to wireless wastewater system monitoring devices.
3. Description of Related Art
A municipal sanitary wastewater system is designed to transport waste material for the community. Spillage of waste material is of major concern to the system operator, the municipality, and the ratepayers in the community. Accordingly, these concerns have led to increasing environmental regulations and resultant penalties for sewer overflows.
As a result, efforts have been made in the art to semi-automate and automate the monitoring of wastewater systems as a means of early detection of sewage backups and rising sewage levels in the hopes of correcting such conditions before sewage overflows occur. In doing so, numerous difficulties have been encountered and heretofore not optimally addressed. Generally, the monitoring device, which essentially includes a sensor, a processor, a wireless transceiver, and a power supply, is installed within a manhole of a wastewater system so as to monitor the wastewater level and report an overflow condition through a wireless alarm transmission. Inherently, the monitoring device is exposed to the contaminating and corrosive environment of the wastewater system, often leading to premature failures of the devices. Further, by locating the monitoring device in the manhole of the wastewater system, additional difficulties are encountered in attempting to get the wireless signal out of the manhole, as the signal is attenuated or interfered with primarily by the iron manhole cover. Often, to overcome the signal attenuating effects of the manhole, a stronger signal from the monitoring device is required, leading to increased device costs, power consumption, and even wireless airtime.
The following art defines the present state of this field:
U.S. Pat. No. 3,735,638 to Miller is directed to a liquid level measurement device relying upon the principle of a resistance bridge wherein the height sensing means is one resistor of the bridge. The height sensing resistor is comprised of a fine wire extending from the bridge circuit to a grounding rod. The fine wire extends generally parallel to, but spaced from, the grounding rod in order to constitute the height sensor. In use, the height sensor is inserted in the liquid whose height is to be measured in such a way that the grounding rod and the fine wire extend generally perpendicular to the liquid level line. Thus, the aqueous ionic media whose height is being measured will short out that portion of the fine wire below the liquid level to decrease the effective resistance of the height sensor. This has the effect of unbalancing the bridge circuit to give a reading on a meter that is an indication of the height of the liquid.
U.S. Pat. No. 4,136,561 to Mueller et al. is directed to a control module having circuitry for generating control and timing signals and for receiving digital data. A plurality of sensor modules are connected to the control module and each contains devices for sensing various physical characteristics, such as water level, rainfall or the like. In response to control signals generated by the control module, each of the sensor modules is operable to input digital data representative of the sensed physical characteristics to the control module. A recorder is connected to the control module and includes a removable recording cassette for recording the digital data transmitted from the sensor modules. The recorder also records the identification of the sensor module transmitting data, along with the calendar day and the time of day that the data was transmitted.
U.S. Pat. No. 4,335,606 to Michalak is directed to an apparatus for measuring the level of at least one fluid and includes an elongated transparent tubular member open at both ends, one of the ends being vertically insertable into the fluid to a reference point below the fluid surface to establish a column of the fluid in the tubular member having a length generally equal to the distance between the reference point and the fluid surface, a stiff tether slightly longer in length than the tubular member and threaded therethrough, a plug connected to one end of the tether for closing at least the inserted end of the tubular member prior to withdrawing it from the fluid to contain the column of the fluid in the tubular member for measurement after the tubular member is withdrawn from the fluid, and a grip connected to the other end of the cable for remotely controlling the plug to close the inserted end of the tubular member. In the process of measuring the fluid level, the column of the fluid can be viewed through the tubular member to check for abnormalities in the fluid and the presence or absence of other immiscible fluids.
U.S. Pat. No. 5,608,171 to Hunter et al. is directed to a distributed, unattended wastewater monitoring system that uses advances in low-energy signal processing and distributed microelectromechanical systems and that involves wireless interrogation of distributed, low-power, normally-off sensors. In a preferred embodiment, a plurality of flowmeter stations and at least one rain gauge station are networked through a base station for storm water discharge of infiltration-inflow monitoring. Wireless transceivers are used to transmit radio signals into and out of a sewer manhole.
Japanese Patent App. No. JP 2002/054167 to Pentafu et al. is directed to a remote monitor for a manhole provided with a sensor part installed in the manhole within the area of a cellular phone network, a data logger part whereinto a measured value from the sensor part is input, a communication device part for emitting the data from the logger part as an electromagnetic wave, a power source part for driving the sensor part, the logger part and the device part, and a central processing part for receiving the electromagnetic wave from the device part through the network. The device part and the source part are housed in the storage part, installed below a cover body of a manhole cover having a through hole closed by the cover body, the cover body eliminating the interception of the electromagnetic wave.
U.S. Pat. No. 6,507,686 to Heinz et al. is directed to a cable network with a light waveguide cable which is introduced in the pipeline of an existing pipeline system. The light waveguide cable is arranged along a line, preferably at the vertex of the pipeline, and is provided with a protective layer so that a smooth transition exists between the wall surfaces of the pipeline and the cable.
Japanese Patent App. No. JP 2003/074081 to Megumi et al. is directed to a remote monitoring device provided with a battery, an opening-closing detecting switch for operating according to opening-closing of a manhole cover, a power supply unit for starting power source supply from the battery by operation of the opening-closing detecting switch and stopping the power source supply by receiving a power supply stopping signal, a controller for starting operation by the power source supply by the power supply unit and outputting transmission data including information capable of specifying a manhole, a communication unit having a transmission circuit for starting operation by the power supply unit and transmitting the transmission data from the controller to a management center via an antenna, and a receiving circuit for receiving the signal from the management center via the antenna and transmitting the power supply stopping signal to the power supply unit.
U.S. Patent App. No. US 2003/0192379 to Ridenour et al. is directed to an apparatus and a method for monitoring a liquid level in a 4–20 mA closed loop system. A process instrument and a measuring unit are powered for a predetermined time and power is provided by a battery.
The prior art described above teaches a liquid level measurement device, an apparatus for automatically sensing and recording data in a sewage system, an apparatus and method for measuring fluid, a distributed, unattended wastewater monitoring system, a remote monitor for manhole, a cable network with light waveguide cable for installation in pipelines of existing supply line systems, a remote monitoring device of manhole, and a water well monitoring system, but does not teach a wireless wastewater system monitoring apparatus wherein the processor/transceiver unit is located outside of the wastewater system or wherein the fluid level sensor's microprocessor is continuously powered while the processor/transceiver unit is only powered and a wireless signal sent when an overflow condition in the wastewater system is detected. The present invention fulfills these needs and provides further related advantages as described in the following summary.